Composite structures sometimes have localized areas containing one or more inconsistencies that may require rework in order to bring the structure within design tolerances.
In the past, one rework process was performed using a patch that was placed over the inconsistent area and secured to the parent structure using mechanical fasteners. This rework technique was desirable because the condition of the patch could be monitored over time by visually inspecting the fasteners. However, the use of fasteners may increase aircraft weight and/or drag on the aircraft, and may be esthetically undesirable in some applications.
In other applications, rework patches have been secured to a parent structure using a bonded joint, however this technique may also require the use of mechanical fasteners that provide secondary load paths forming an arrestment mechanism to limit the growth of an inconsistency. Furthermore, changes in a bonded joint securing a rework patch on a parent structure, such as the advance of a disbond, may not be easily monitored over time because the attaching mechanism of the joint or joint interface may not be visible.
Accordingly, there is a need for a bonded patch used to rework an area of a structure that controls possible changes in the bond joint in a manner that allows the changes to be detected and/or predicted over time. There is also a need for a method of controlling the advance of a disbond in the patch.